40 MHz Scouting for BRIL

Different luminometers like PLT (Pixel Luminosity Telescope), BCM1F (Fast Beam Condition Monitor) and HF (Hadronic Forward Calorimeter) are used to measure luminosity at CMS. In Run 2, DT (Drift Tubes) were used for stability and linearity cross checks, which use rates of muon tracks in the muon barrel track finder. However, DT do not provide bunch-by-bunch measurements and can therefore only be used for total luminosity measurement. [1] At the end of Run 2 the new data acquisition technique “40 MHz Scouting” was tested. It provides per bunch DT data, which is necessary for stability studies. With “40 MHz Scouting” the events are not filtered by triggers and therefore much more data is available for analysis and other tasks. From this follows that the size of each event must be reduced to a minimum because storage space is limited. Therefore, 40MHz Scouting opens the possibility to do analysis with full statistics or searches in regions excluded by triggers, by making use of HLT objects with reduced accuracy. [3]